public class Circle {
    private double radius; // 半径

    public Circle(double radius) {
        this.radius = radius;
    }

    public double getCircumference() {
        return 2 * Math.PI * radius;
    }

    public double getArea() {
        return Math.PI * radius * radius;
    }

    public static void main(String[] args) {
        // 创建一个Circle对象，半径为5
        Circle circle = new Circle(5);

        System.out.println("圆的周长: " + circle.getCircumference());
        System.out.println("圆的面积: " + circle.getArea());
    }
}
